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Geophysical features and crustal structure of the East China Sea basement were revealed based on geophysical inversion analysis with recent gravity and magnetic data. Our results show great differences between the East China Sea continental shelf basins and the Zhemin Volcanic Belt in the coastal South China Block with respect to geophysical features and crustal structures. These areas are separated by distinct geophysical and crustal changes, approximately along a line 100 km from the coastline of China. We hypothesize that the East China Sea basement is a buoyant allochthon in the Palaeo‐Pacific Plate, and that the East China margin was an Andean‐type active continental margin until the collision of the East China Sea basement with the South China Block in the Late Cretaceous, which jammed the Late Cretaceous Trench, terminating the subduction and the related granitoid magmatism. The East China continental margin was dominated by dextral transtension with limited magmatism due to the NNW‐trend motion of the Palaeo‐Pacific Plate with a reduced convergence rate until the Middle Eocene. The renewed westward subduction of the present‐day Pacific Plate replaced the East China Andean‐type continental margin with a Western Pacific‐type one. The detailed reconstructed tectonic model for the East China Sea since the Mesozoic is presented in this paper. [ABSTRACT FROM AUTHOR]

The ocean-continent transition/conjunction zone is a mysterious and significant region in global tectonics and geodynamic evolution. The South China Sea (SCS) is one of the largest marginal basins in the Western Pacific with significant Cenozoic magmatic activities. The relationship between the tectono-magmatic evolution and the tectonic setting of these Cenozoic igneous rocks is still controversial. In this study, the interpretation of gravity data, magnetic observation and seismic profiles is combined to identify the Cenozoic igneous rocks in the SCS and adjacent regions, and more than 70 magmatic activities have been discerned. We also show how the tectonic movements control the lithology and distribution of these magmatic activities. These Cenozoic magmatic rocks are related to the pre-spreading, syn-spreading and post-spreading of the SCS. We suggest a geodynamic evolution of the SCS according to the temporal and spatial distribution of the igneous rocks. (1) An early period of bimodal volcanism (>32 Ma ago) mainly happened in the Paleogene basins at the northern margin of the SCS. This earlier volcanism happened under a trans-extensional regime, which resulted from the collision between the Indian and the Eurasian plates since the early Cenozoic. The magmatic rocks may be related to the NNE-trending right-stepping dextral strike-slip faults and the syn-kinematic pull-apart basins. These igneous rocks are mostly NNE trending. It is consistent with the Cenozoic dextral trans-extensional tectonic setting in the East Asian Continental Margin. (2) Syn-spreading igneous rocks first formed in the Northwest Sub-basin of the SCS, and then later in the Central and Southwest sub-basins. The mechanism of the magmatic emplacement results from the NNE-trending right-stepping dextral strike-slip pull-apart tectonic activity. (3) The spatial alignment of the Quaternary post-spreading basalts is nearly E-W-trending, and the different magmatic zones are segmented by NNE-trending strike-slip faulting. These volcanics are under an extrusion regime, which resulted from the arc-continent collision between the Luzon-Taiwan Arc and the Eurasian Plate due to the continuously WNW-directed indentation of the Philippine Sea Plate during the period 9-6 Ma ago. In addition, the nascent NNE trending and dextral Changle-Nanao Fault may have played a significant role in the southward extrusion of the Taiwan Island Arc and the southeast SCS, resulting in an E-W-trending distribution or strike of the volcanics and normal faults. In Indochina and the Malay Peninsula, widespread Cenozoic extensional post-spreading granitic plutons are possibly derived from the mantle plume. Magnetic anomaly interpretation and tectonic analysis on these mafic rocks suggest that they were controlled by the Ailaoshan Red River left-lateral ductile strike-slip fault zone. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Earth system includes Earth's surface system and deep Earth system. This Special Issue tries to establish a link between these two systems. It contains 46 contributions on Earth system evolution of the Pacific and Indian oceans and the South China Sea. The themes cover the relationship of ocean to continent, tectonic jumping, morphotectonics in the continental margin, back-arc basin formation, formation of transform faults, subduction retreat, hot and cold subduction, actions of typhoons, plume-tail-related hydrothermal activity, sediment transportation and dynamics and others. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Multichannel seismic data on the continental shelf have been used to image the rift-related shallow structural units of the Pearl River Mouth Basin across the northwestern margin of the South China Sea. The Hainan Uplift, Zhu 3 Depression and Shenhu-Ansha Uplift zones are bounded by normal faults or listric-normal faults, which suggest lithospheric extension on the continental shelf. Graben structures 10-15 km wide are imaged on the Wanshan Uplift and Northern Fault Terrace from the reflection data. The thinned continental crust and anomaly rift-related crust in the depression zone and the transitional crust indicated by the wide-angle OBS velocity model dominate the crustal structure of the continental shelf in the continental margin of the South China Sea. The different total crustal stretching factors in different shallow structural units suggest that non-uniform horizontal stretching controls the crustal thinning. The total crustal stretching factor is ca. 1.4-1.6 at the coast area, ca. 1.67-1.8 in the rift-depression zone and ca. 1.7-1.75 in the transitional crustal domain. Pure-shear crustal thinning controls the crustal extension in the rift-depression zone. The high heat flow anomaly in the vicinity of the seismic lines and anomaly rift-depression velocity structure suggest that the crustal thinning on the continental shelf of the South China Sea can be produced by lateral mantle flow within the hotter regional lithospheric background. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The northern South China Sea (NSCS) experienced continuous evolution from an active continental margin in the late Mesozoic to a stable passive continental margin in the Cenozoic. It is generally believed that the basins in the NSCS evolved as a result of Paleocene–Oligocene crustal extension and associated rifting processes. This type of sedimentary environment provides a highly favourable prerequisite for formation of large-scale oil- and gas–fields as well as gas hydrate accumulation. Based on numerous collected data, combined with the tectonic and sedimentary evolution, a preliminary summary is that primitive coal-derived gas and reworked deep gas provided an ample gas source for thermogenic gas hydrate, but the gas source in the superficial layers is derived from humic genesis. In recent years, the exploration and development of the NSCS oil, gas and gas hydrate region has provided a basis for further study. A number of 2D and 3D seismic profiles, the synthetic comparison among bottom simulating reflector (BSR) coverage characteristics, the oil-gas area, the gas maturity and the favourable hydrate-related active structural zones have provided opportunities to study more closely the accumulation and distribution of gas hydrate. The BSR has a high amplitude, with high amplitude reflections below it, which is associated with gas chimneys and pockmarks. The high amplitude reflections immediately beneath the BSR are interpreted to indicate the presence of free gas and gas hydrate. The geological and geochemical data reveal that the Cenozoic northern margin of the NSCS has developed coal-derived gas which forms an abundant supply of thermogenic gas hydrate. Deep-seated faults and active tectonic structures facilitate the gas migration and release. The thermogenic gas hydrate and biogenic gas are located at different depths, have a different gas source genesis and should be separately exploited. Based on the proven gas hydrate distribution zone, we have encircled and predicted the potential hydrate zones. Finally, we propose a simple model for the gas hydrate accumulation system in the NSCS Basin. [ABSTRACT FROM AUTHOR]